It’s not often that I write the words “big news” and “PBS” in the same sentence, but there are several items of note regarding the Public Broadcasting Service.

The network’s biggest show, “Downton Abbey,” will return for its fifth season on Sunday, Jan. 4, PBS president Paula Kerger announced Tuesday. “Downton” is now the most popular show in PBS history after averaging 13.2 million viewers last season, up from 11.5 million viewers the season before.

There’s no official airdate for the show’s Season 5 premiere in the UK, but it’s believed it will be in mid- to late September. “Downton Abbey” averaged 11.8 million viewers on Britain’s ITV last season and was England’s top-rated show. Elizabeth McGovern, Maggie Smith, Hugh Bonneville and Joanne Froggatt are among the stars who will return next season.

Prior to “Downton Abbey,” PBS’ biggest-ever draw was the Ken Burns documentary “The Civil War” — so it all ties together nicely that PBS also announced Tuesday that Burns’ upcoming 14-hour documentary, “The Roosevelts,” will be available online (local station sites and the PBS site), in its entirety, the day after its Sept. 14 premiere. It will air for seven consecutive nights on PBS.

Meanwhile, another popular series, “Call the Midwife,” will air “The Midwife Holiday Special” on Sunday, Dec. 28, on PBS before returning for its fourth season March 29. The series averaged 3.6 million viewers last season (but attracts a much bigger audience on BBC One in England).

TV world’s sad news

Acclaimed writer John Fasano, who boasted a strong resume of television work, died in his sleep Saturday night in LA at the age of 52.